These uninterrupted power supply (UPS) systems generally comprise a central system level hardware for connecting the UPS systems to a power distribution, for which uninterrupted operation has to be achieved. Hence, the system level hardware may comprise customer cable landings, bypasses, switch gears, system user interfaces and so on. This system level hardware can be provided commonly in an input/output (I/O) enclosure.
Typically, the UPS system further comprises at least one, usually multiple converters, also referred to as uninterrupted power supply modules, which store electrical power to provide it via the I/O connection enclosure to the power distribution. Number, size and power rating of the converters are chosen depending on the UPS system design based on customer requirements. In this area, UPS power systems with a power of at least 100 kW are common.
The converters are typically arranged in single, free standing enclosures, which are connected in parallel for providing power of at least tens of kilowatt. Accordingly, the converters can be provided in the enclosures side by side to each other, which enables formation of high power UPS systems. Also parallel connection of single converters through hard wired cabling to a common I/O enclosure is known. Accordingly, the converters are hard wired, e.g. by cables, to a central I/O enclosure.
Due to hard wiring and large building blocks, i.e. large enclosures for the converters, the above UPS systems are difficult to service, since removal of the converters is a major operation, and modification of the UPS system, e.g. an adaptation due to changed power requirements, resulting in an addition, removal or substitution of converters, is rather complicated, labor intensive and time consuming, since cable connection has to be disconnect and interference from adjacent enclosures and/or converters can occur, especially for a converter that is not located at an lateral end of a row. Also service safety can be very poor.
Even when cables are replaced by bus bars, the converters still have to be connected to the bus bars, so that the individual cabling effort for connecting the converters remains. Furthermore, the use of bus bars may reduce air circulation capabilities of the UPS system. Accordingly, the trend for hot/cold aisles and closed air paths can be compromised due to bus bar setup.